Fluid-driven impact mechanism



Dec. 26, 1950 T. E. MEAD 2,535,588

FLUID-DRIVEN IMPACT MECHANISM Filed Aug. 20, 1945 2 Sheets-Sheet 1 Patented Dec. 26, 1950 UNITED STATES PATENT OFFICE FLUID-DRIVEN IMPACT MECHANISM Theodore E. Mead, Wilmette, 111.

Application August 20, 1945, Serial No. 611,521.

4 Claims. (01. 12l--13) lhis invention relates to fluid-driven mechanism. It is particularly useful in connection with an air-hammer.

An object of the invention is to provide mechanism under which a fluid-driven element is temporarily held against movement until a predetermined pressure has developed whereby the full force of the pressure is obtained in. the power stroke. A. further object is to provide fluid-driven mechanism in which simple and automatic means are provided for arresting the movement of the power member until a predetermined pressure has been built up and then releasing the power member. Yet another object is to provide mechanism in which a fluid-driven member is held under adjustable control means and released only after a selected pressure has been reached. A further object is to provide airhammer mechanism which may be employed manually or under an automatic control for striking a blow under a predetermined pressure, the stroke f the hammer being held in check until a selected pressure is obtained. Other objects and advantages will appear as the specification proceeds.

The invention is illustrated, in a preferred em.- bodiment, by the accompanying drawings, in which Figure l is a side view in elevation of apparatus illustrating one embodiment of my invention; Fig. 2, a broken top plan view of the same; Fig. 3, a transverse sectional view, the section being taken as indicated at line 3 of Fig. 1; Fig. l, a vertical sectional view showing the plunger held against movement; and Fig. 5, a broken view similar to Fig. 4 but showing the plunger in a lower position of its stroke.

While the invention is applicable to any form of fluid-driven mechanism under pressure, it will be described herein for the purpose of clearness in connection with an air-hammer which represents one embodiment of the invention.

In the illustration given in Figs. 1 to 5 inclusive, A designates a support member; B, a bracket member; and C, air-hammer mechanism.

Any suitable supporting apparatus may be employed. In the illustration given, the structure A comprises a base l0 and a vertical standard H having a. bracket-supporting portion l2.

The bracket structure B includes a sleeve portion 53 having. a split rear portion equipped with flanges l4. clamped. about the shaft l2 by bolts l5. Integrally formed with the sleeve or collar l3. and extending forwardly is a bracket member l6 which is split at its forward end and. adapted 2 to recei'vc a power cylinder H The member I6 is clamped tightly about the cylinder H by the bolts 18-.

The cylinder H is interiorly' threaded at its upper end and threadedly secured to a boss t5 provided by the casing head 28. A housing 2! which isv integral with upper transverse web 21a and the lower web 22, extends aboutand provides a vertical chamber just forward of the bracket member it. The lower wall or web 22 receives the lower end of cylinder" H.

The head casing 26 also threadedly receivese a cylinder 23. in which is mounted a piston 2i fixed to. the actuating rod 25. A port 26- leads within the head 20 to the top portion of cylinder 23 and another passage. 2! leads to the top portion of the cylinder ll. Both passages 26 and 21 lead into a manifold 28 tapped at one end to: receive the coupler 29 adapted to receive the usual valve-equipped tube (not shown) leading from a source. of air pressure.

Cylinder $1 and cylinder 23: are secured within the upper transverse web 21a by setscrews (not shown) or any other suitable means.

Within. the power cylinder I! is mounted a plunger 30 provided. at. its upperend with a piston or sealing: member 31.. Near its lower end, the plunger 30. is provided with a notch. or groove 32 and below the. groove. or notch with. a fixed pin 33- secured, at. its outer end: to: a. spring member 34 adapted to return the plunger after its downward stroke. The spring 34 is. preferably housed within a tube 35 which is fixed in the webs. Zia and 22, the top end: of the spring being supported by a screw or pin 36..

The actuating. rod 25 extends through. thebottom wall 22. and engages a pivoted tri lock 31. The member. 3'! is housed within a chamber provided by the lower portion of the housing 2! and a bracket member 38. secured thereto by welding or by any other suitable means- The. member 38 is provided with a lug 39 to which the member 31- is pivoted. Member 38 is also. tapped. to receive the hollow adjustment. screw 4.9 which. is provided with a knurled head 4 l Received within the screw 40 isan: adjustment spring 42 which bears against the arm of the. trip. member 3]. The. member 31 is preferably provided with a scar 43 adapted to. engage the groove or notch. 32 of plunger 30 to maintain the plunger against downward movement. The member 3'! is preferably extended to provide a. handle 31a. which extends through a slot in housing 2| for manual operation if desired.

The plunger 30 may be provided with any work member or tool at its bottom portion. In the illustration given, an indentation-forming member 44 is shown. It is understood that the plunger will be equipped with any suitable member for accomplishing the desired type of Work.

In the operation of the device, air is admitted through the valve-controlled line communicating with fitting 29 and flows through passages 26 and 27 into the upper portion of cylinders a3 and I! respectively. Plunger 30 is held against downward movement against the pressure fluid within the upper portion of the cylinder. However, when the pressure within cylinder 23 reaches a predetermined point, the piston 24 and actuating rod 25 move downwardly and swing the arm of the trip member 31 downwardly against the force of spring 42 and withdraw the sear 33 from engagement with groove 32. lhe plunger 3%! then descends under the full power of the accumulated pressure within the upper end of cylinder ll. By this means, the hammer or plunger 38 strikes with high iorce and a regular or controlled force with each stroke. The adjustment member as permits the tension upon spring 2 to be adjusted to thus regulate the pressure at which the plunger will be released.

When the plunger swings to its lower position, as illustrated in Fig. 5, the operator, by cutting off the valve controlling the how of ar to fitting 29, permits the air to be exhausted back through fitting 29 and the outlet port of the valve (not shown). Spring 34, which was tensioned during the downward stroke of the plunger as, now returns the plunger to its initial position, as illustrated in Fig. 4.

In forming an indentation with the specific tool illustrated, the operator will move the piece of work upon the base Iii to the desired point and then open the compressed air valve. The piston 3:) will not move downwardly under the first impulse of the compressed fluid reaching the cylinder, but is retained against movement until a predetermined pressure has been built up. At that moment, the member 37, through the operation of actuating rod 25, releases the member 39, and it strikes to form an indentation of the desired depth. Each subsequent indentation in the material will be of the same depth unless the adjustment spring 52 is tensioned to a different extent through the rotation of screw 4%.

While I have shown the release of the trip member 3? dependent upon pressure of the fluid as against a controlled spring, it will be understood that the trip member 37 may be operated manually through handle Ella. In the automatic structure shown, a precise control of each stroke of the hammer, as to its intensity or power, is efiected through the use of the actuating rod and spring structure illustrated, and the operator is free to give his full time to the actuation of the airline valve which will control the number ofstrokes.

While in the foregoing description I have set forth certain specific apparatus as illustrative of the invention, it will be understood that the invention has broader application and that the details of the structure herein set out may be modified widely by those skilled in the art in utilizing it in such other applications.

I claim:

1. An air-hammer comprising a casing, a cylinder supported thereby, a work plunger mounted in said cylinder for a longitudinal stroke therein and having a portion extending beyond said cylinder, means for admitting air under iii pressure into one end portion of said cylinder to exert pressure upon said plunger, means adjacent the other end of said cylinder but outside the same for preventing movement of said plunger until a predetermined pressure has been built up, said means releasing said plunger under said built-up pressure or in response to manual actuation at the option of the operator, said lastmentioned means including a pivotally-mounted member, cooperating means carried by said pivotally-mounted member and said plunger for normally restraining movement of said plunger, means carried by said pivotally-mounted member permitting manual actuation thereof to release said plunger, 9. second cylinder, a piston in said cylinder, a rod carried by said piston and adapted to actuate said pivotally-mounted member to release said plunger, and a spring engaging said pivotally-mounted member and normally urging the same against said actrating rod.

2. An air-hammer comprising a casing, a cylinder supported thereby, a Work plunger mounted in said cylinder for a longitudinal stroke therein and having a portion extending beyond said cylinder, means for admitting air under pressure into one end portion of said cylinder to exert pressure upon said plunger, means adjacent the other end of said cylinder but outside the cylinder for preventing movement of said plunger until a predetermined pressure has been built up, said means releasing said plunger under said built-up pressure, said last-mentioned means including a pivotally-mounted member, cooperating means carried by said pivotally-mounted member and s id plunger for normally restraining movement of said plunger, a second cylinder, a piston in said cylinder, a rod carried by said piston and adapted to actuate said pivotallymounted member to release sa d plunger, a spring engaging said pivotally-mounted member and normally urging the same against said actuating rod, and means for adjusting the tension of said spring.

3. In fluid-driven mechanism, a head casing, means for supporting the same, a work cylinder having its upper end mounted in said casing, a trip-control cylinder having its upper end mounted in said casing, said head casing providing a manifold and ports leading therefrom to said cylinders, means for supplying fluid under pressure to said manifold, a work plunger mounted in said work cylinder and having a portion extending beyond the lower end of said cylinder, a piston mounted in said trip-control cylinder, trip means exterior of said cylinders and cooperating with said extended portion of the plunger and normally preventing downward movement of said plunger, means associated with said piston for actuating said trip means to release said plunger, and manually-operable means for actuating said trip means without moving said piston.

4. In fluid-driven mechanism, a head casing, means for supporting the same, a work cylinder having its upper end mounted in said casing, a trip control cylinder having its upper end mounted in said casing, said head casing providing a manifold and parts leading therefrom to saidcylinders, means for supplying fluid under pressure to said manifold, a work plunger mounted in said work cylinder and having a portion eX- tending beyond the lower end of said cylinder, a piston mounted in said trip control cylinder, trip means exterior of said cylinders cooperating with said extended portion of the plunger and normally preventing downward movement of said plunger, said trip means including means permitting manual release of the trip means without dragging the piston in the trip control cylinder, and means associated with said piston for actuating said trip means to release said plunger.

THEODORE E. MEAD.

REFERENCES CITED The following references are of record in the file of this patent:

Number 6 UNITED STATES PATENTS Name Date Short Aug. 15, 1899 Rogers July 9, 1907 Patterson Feb. 1, 1916 Scott May 4, 1926 Gartin Aug. 10, 1937 Engel Dec. 6, 1938 Lenz Nov. 14, 1939 Clark May 6, 1941 Daalder Feb. 2, 1943 

